Border Tunnels, Part 5

How To Detect Tunnels.

Sometimes it is good to help people understand exactly what can be done to solve a problem. This can be especially good when the opposition is reading the same book. In the present case, all the smugglers in "Tunnel Land" can read the following and be warned.

Let’s examine some technology from World War Two or even from before World War One and see how it can apply to detecting tunnels along the border. And let’s not worry about the simple tunnels linking to existing storm drains but instead look at the really sophisticated ones costing tens of millions of dollars to construct.

There are two general methods for finding such tunnels using seismic activity. While there are other tunnel detection methods available only muon detection (discovered in 1911 and used by that 12 year old boy to find tunnels) comes close in accuracy and effectiveness as a persistent surveillance mechanism.

If one installs seismic detectors within the “No Man’s Land” along the built up areas of the border, it is possible not only to detect the digging noises of tunnel construction but the distant removal of the dirt and its transport to a dumping area.

Digging noises can be masked to some degree by changing the digging method. Low frequency digging noises – the thump, thump, of a shovel or pick – can be detected at a quarter mile in hard earth. If higher frequency tools are used then the sound is quickly absorbed and detection at distance is made more difficult.

Because no tunnel has been built with its southern tail longer than 2,000 feet below the border, the detection range for tunnel construction probably need not exceed 50% more than that or 3,000 feet.